Transforms (Image Processing Toolbox)

Image Processing Toolbox

Terminology

An understanding of the following terms will help you to use this chapter. Note that this table includes brief definitions of terms related to transforms; a detailed discussion of these terms and the theory behind transforms is outside the scope of this User's Guide.

Terms
Definitions

Discrete transform
A transform whose input and output values are discrete samples, making it convenient for computer manipulation. Discrete transforms implemented by MATLAB and the Image Processing Toolbox include the discrete Fourier transform (DFT) and the discrete cosine transform (DCT).

Frequency domain
The domain in which an image is represented by a sum of periodic signals with varying frequency.

Inverse transform
An operation that when performed on a transformed image, produces the original image.

Spatial domain
The domain in which an image is represented by intensities at given points in space. This is the most common representation for image data.

Transform
An alternative mathematical representation of an image. For example, the Fourier transform is a representation of an image as a sum of complex exponentials of varying magnitudes, frequencies, and phases. Transforms are useful for a wide range of purposes, including convolution, enhancement, feature detection, and compression.

Terms	Definitions
Discrete transform	A transform whose input and output values are discrete samples, making it convenient for computer manipulation. Discrete transforms implemented by MATLAB and the Image Processing Toolbox include the discrete Fourier transform (DFT) and the discrete cosine transform (DCT).
Frequency domain	The domain in which an image is represented by a sum of periodic signals with varying frequency.
Inverse transform	An operation that when performed on a transformed image, produces the original image.
Spatial domain	The domain in which an image is represented by intensities at given points in space. This is the most common representation for image data.
Transform	An alternative mathematical representation of an image. For example, the Fourier transform is a representation of an image as a sum of complex exponentials of varying magnitudes, frequencies, and phases. Transforms are useful for a wide range of purposes, including convolution, enhancement, feature detection, and compression.

Transforms Fourier Transform